Projection apparatus



June 24, 1930. K. 'BRENKERT El' AL PROJECTION APPARATUS Filed April 25 l lf @noruega Patented June 24, 1930 f- UNITED STATES PATENT OFFICE KARL ERENKERT AND JOSEPH w. BRENKERT, or DE'iRori, MICHIGAN PROJECTION APPARATUS Application iiled April 25, 1927. Serial No. 1863206.

' The present inventionpertains to a novel ployed to designate corresponding parts projection apparatus designed particularly throughout.

for"stereo'pticonl purposes. The apparatus is built on a housing l The principal object of the invention is having a track 2 on itsA base. A carriage to provide atwo-unit vdevice of this char- 3 slides on the .base and is provided with a 55 acter using only one light source as comvertical arni 4r in which is rotatably mountpared with two light sources employed in ed a horizontal stem 5. rThis stem passes suoli `devices of present construction. It has through a horizontal slot 6 out iii one of the been found that asingle light source inwalls of the housing 1, as shown in Figure 10 stalled according to this invention effectsa 1, and is provided with a turning head 7. 60 saving VapproXimately lifty per cent in A reflector 8 is supported on the stem 5 by electrical energy. A a boss 9 formed on the reflector and having The vprovision of a single light source for the stein anchored therein. The carriage 3 va two-unit projector operating alternately further includes a rail 10 having slidably through its two lensassemblies raises the mounted thereon arms ll'and l2 disposed 65 problem of arranging thesel sets oflenses at opposite sides of the reflector. These in such'amannerthat both will project upon arms support carbon rods 13 and lll posia single givenV area ofthe screen. At the tioned to yform a light crater on the concave vsaine time the device of the invention is side of the reflector. The arms are rformed .d20 adapted to project on two different areas, with internally threaded ears 11n and 12a '70 one above the other. receiving screws 111 and l2b which are The latter case is the simpler, and merely journaled in suitable bearings l1c and 12'l requires a beam of parallel rays issuing provided on the carriage.

from the light source and divided by the The reflector 8 is of a type adapted to 25 two lens assemblies.` To project both lens produce parallel or converging rays, de- 75 assemblies upon a given area of the screen, pending on the position of the light crater various modifications and a'djustments are with reference to the focal point. A paranecessary." The problem involved is niet by bolic reflector is suitable for this purpose, mounting the `light source movably along for such a member provides parallel beams 4r30 the axis of a parabolic reflector so that conwhen the light crater is at thefocal point A80 verging as well as parallel rays may be oband converging beams when the crater is tained. yThe converging beam may be didisposed forwardly of the focal point. The vided equally between the two lens assenirelationlbetween the light crater and the o lolies7 'and the divisions projected upon a focal point of the reflector may loe varied by ksi; given area of thev screen, by peculiar adadjusting the screws l1h and 121. The re- '35 justmeiits'of the reflector and at least one HeCtQ is also tumble 0n the ba'ng SUP Setof lenses. porting the stem 5, and the Iobject of this `The invention is fully disclosed by way @ldlustmenbwn pm sently be described' 'itt of example in the following description and saldo 5 0 be noted that whim the Stem au15 inthe accompanying drawing, in which slid inv the slot 6, the relation between the 90 Fio'urel is a plan view of the apparatds; emboli. lds 13 and M 1S n-Oi Change@ b?- .2=- 1 t. t1 er 0L. on the cause their supports move with the carriage Flg- 2 1S a Yetlca .Sec lon 'l e t 3. The relation of the rods is changed by hn@ 2*-2 0f Flgufe l operation of the screws 11b and 121.

4'5 Fig 3 is a longitudinal` Wltcal Section; rlhe front wall l5 of the housing l has 95 andV Y apertures` 16 and 17 one' over the other. Flgnd 1S a diagrammatic @lGVatlOIl ShOW At the aperture 16 is mounted a guide 18 ing the projection upon the screen. having a vertical path, and a condensing Reference to these views will now be made lens 19 is mounted in the guide. The lens 5o byuse of like characters which are em- Structure has a lateral ear 20 in which is '100 threaded a vertical screw 21 journaledV in a bracket 22 fixed to the housing 1. The

screw is operated'by a hand wheel 23. It will be seen in Fi ure 3 that the aperture `16 is of sufiicient eight to permit adjustgp member 29 has a lateral ear' 30 into which is a screw: 31 vhaving a hand wheel 32 Aand journaled in a bearin 33 at the u perl end of the member 28. his member a carries a lower focusing lens structure ,9,5 34 in line with the member 24. The member 34 need not bey adjustable if the lmember 24 is fixed. The supportin ystandard 28 may be adjustable on the r 27 if desired, and the latter member may be: substituted other suitable supporting device that by 211g' may e especially adapted for special conditlons. u

Figure 3 illustrates the light source and refiector arranged for projecting parallel rays in` which case the light crater is at the focal oint of the reflector. ',The beam is divide by the condensing lenses 19 and 24 and projected through the lenses 29 and 34 towards two areas, one over the other, on the screen.

In most cases Vv,however it is desired that theprojections be made alternately from the two unitsupon one area of the screen. The alternation, is effected by the dissolving shutters in av manner already well known in the art. For this mode of operation the ra l must be converged, and this is accomplished by moving the light crater forwardly'- ofthe focal point of the reiector in the manner.V already described. The rays will then converge on aline passed horizontally between the lenses4 and will` forlthe most part evade the lenses. A suicient section of the beam is directed through. the lower set of lenses by merely tilting the reflector forwardly, as in Figure 4,` b turning the stem 5, and the upper set of lenses receives less light than formerly. These lenses are however adjustable yverticall so that they may-be brought into the path of the upper half of the beam.`

It is also to be noted that this device dif fers from the movable head type by having onl. one light source supplying botli'units. It s been found that a single light source tion beingy adjustably mounted, and means for arrangedl in this manner enables a saving of approximately fifty percent of the electrica energy consumed in a two-unit machine.

The disclosed means of deilecting ons of the beam divisions so that its projection registers withthat of thao'ther division is mei-elly illstrajtie. Any. mutable' device for accom lishing this function may be employe such as a wedge prism for exampleV stead of the upper; one. might require a change in direction.

Although aspeciic embodimentoi their#V ventionr has been illustrated-anddcseribed;

it will be understoodthat various alterations in the details of constructionmay be made without departing from the scope ofV the inventionas indicated, by theappendod claims.

What, we claimisz- 1. A projector comprising a light' source,

a tiltably mounted lconcave reflector to produce a converging beam, means for tiltln said reflector, a pair (lf-,lenses posi'- to divide the beam, one of said. lenses.

adjusting said lens to follow its division of the kbeam on tilting of said reflector.

2. A. projector comprising a light source, atiltably mounted concave reflector adapted to produce a converging beam, means .for tilting said reliector, a air of cond lenses positioned to vdivi ethe beam, ing lenses. in advance of said condensing lenses, one of said condensing and focusing lenses being adjustably mounted, and'meani for ad'usting said lens to follow the cor: respon in division of thebeam on tilting of said re ector.

3, A projector comprising a light sources a tiltably mounted concave reflector adapted to produce a@ converging. beam, mem-S, fr tilting said reflector, a pair of lenses oglio above the other and positioned to divide the beam, the upper lens being adjustably mounted, and means for adjusting said lens to follow its division of the beam on tliting of said reiector.

4. A projector comprising a light source, a. tiltably mounted concave reflector adapted to produce a converging beam, means for tiltingsaid reflector, a pair of lenses positioned to divide the beam,.one of said. lenses being adjustably mounted, means for ad- Ajusting said lens to follow. its division of H0 the beam on tilting of said reflector, and

l dissolving shutters at said lenses.

5. A projector comprising a light source,

.a tiltably mounted concave reflector adapted to produce a converging beam, means for tilting said reflector, a pair of condensing lenses positioned to divide the beam, focusing lenses in advance of said condensing lenses, one of said condensing and focusing lenses being adjustably mounted, means for adjusting said lens to follow the corres onding division of the beam on tilting o said reflector, and dissolvingshutters at said condensing lenses.

In testimony whereof We afix our signa-v tures.

KARL BRENKERT. JOSEPH W. BRENKERT. 

